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### #Actualeowdaoc

Posted 13 September 2012 - 10:18 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI, unless you're talking about the actual physical model, not the real time phong model. I guess I should have specified

Also my light position is at ( 5, 5, -5 ) so it's not a crazy distance away or anything. I have it coded so that I can move the light around so I should be able to move it close enough.

I got the 3d model a while ago so I have no clue where it is online but I can upload it somewhere for you (no texture, just v/vn obj file). What's a good free upload place?

Update: I can only get it to light the object if make the equation attenuation = 1.0f / ( d*d*0.00000075 ) or making the light color something ridiculous like ( 999999, 9999999, 99999999 ) but that's kind of silly, there has to be a better way right? Also, using that, I can't get the light to completely "fall off" no matter how far I move it away from the object.

### #6eowdaoc

Posted 13 September 2012 - 08:07 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI, unless you're talking about the actual physical model, not the real time phong model. I guess I should have specified

Also my light position is at ( 5, 5, -5 ) so it's not a crazy distance away or anything. I have it coded so that I can move the light around so I should be able to move it close enough.

I got the 3d model a while ago so I have no clue where it is online but I can upload it somewhere for you (no texture, just v/vn obj file). What's a good free upload place?

### #5eowdaoc

Posted 13 September 2012 - 08:06 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI, unless you're talking about the actual physical model, not the real time phong model.

Also my light position is at ( 5, 5, -5 ) so it's not a crazy distance away or anything. I have it coded so that I can move the light around so I should be able to move it close enough.

I got the 3d model a while ago so I have no clue where it is online but I can upload it somewhere for you (no texture, just v/vn obj file). What's a good free upload place?

### #4eowdaoc

Posted 13 September 2012 - 08:04 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI. I've referenced 3-4 books.

Also my light position is at ( 5, 5, -5 ) so it's not a crazy distance away or anything. I have it coded so that I can move the light around so I should be able to move it close enough.

I got the 3d model a while ago so I have no clue where it is online but I can upload it somewhere for you (no texture, just v/vn obj file). What's a good free upload place?

### #3eowdaoc

Posted 13 September 2012 - 07:54 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI. I've referenced 3-4 books.

Also my light position is at ( 5, 5, -5 ) so it should be close enough even with quadratic attenuation.

I got the 3d model a while ago so I have no clue where it is online but I can upload it somewhere for you (no texture, just v/vn obj file). What's a good free upload place?

### #2eowdaoc

Posted 13 September 2012 - 07:53 PM

Anyway, the reason why things are getting dark is, that your light source is probably too far away. Consider a distance of 10 units in space. Squared and divided gives you 1/100 of your un-attenuated intensity. I think, things should work for you, if you make your light brighter, i.e. your variable “lightColor”. The lightColor actually stores the luminous intensity in candela (cd). A candle has about 1 candela. A 100 watt light bulb has about 130 cd. So, I guess you need rather large values. :-)

By the way, your test model is quite beautiful. Is it available online? I'd like to use it in my thesis.

Cheers!

So my light color, which is currently ( 1.0f, 1.0f, 1.0f ), needs to be something like ( 100.0f, 100.0f, 100.0f )? I tried this but it is still the same result. I am apparently missing some of the logic here. I'm not sure what you are talking about dividing by PI. I haven't seen any diffuse/specular calculations that use PI. I've referenced 3-4 books.

Also my light position is at ( 5, 5, -5 ) so it should be close enough even with quadratic attenuation.

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